SOUTH BEND, Ind. (AP) — Notre Dame coach Brian Kelly sounded hopeful quarterback Tommy Rees will be ready to play Saturday at struggling Air Force after sustaining a neck injury against Southern California.

"He's feeling better today. Still a little sore, but it will be a day-to-day situation," Kelly said Sunday.

Kelly said he expects Rees to practice Tuesday. The Fighting Irish (5-2) probably need Rees to heal quickly after seeing the offense become incapacitated when Rees left the game with a sprained neck with nine minutes left in the third quarter when linebacker Lamar Dawson sacked him.

With backup Andrew Hendrix in the game, the Irish managed just two first downs and the Irish went three-and-out on three other possessions and lost the ball on a fumble on another.

The Irish offense wasn't dominating against USC, but looked solid while Rees was in. Rees completed 14 of 21 passes for 166 yards and two touchdowns in the 14-10 victory.

"We liked the way he played," Kelly said.

Fans might have a renewed fondness for Rees after seeing how the Irish offense looked in his absence.

Rees, who lost the starting job after his sophomore season after throwing 14 interceptions and fumbling the ball away five times in 2011, was roundly booed when he was called on to replace Everett Golson against Purdue in the second game last season.

But his popularity grew as he rallied the Irish to victories last season against Purdue, Michigan and Stanford and started in a victory over Brigham Young and played a significant role in helping the Irish get to the BCS title game.

But questions whether Rees was good enough to lead the Irish to a successful season started as soon as the university announced in May that Golson had been suspended for the fall semester for poor academic judgment.

Rees got off to a good start passing for 300 yards in each of Notre Dame's first three games, though, completing 65 of 107 passes, a 61% completion rate. Rees struggled through the next three games, completing just 42% of his passes with four interceptions as the Notre Dame offense struggled. Some began wondering if he was part of what was wrong with Notre Dame.

Now fans are hoping Rees gets well fast after seeing Hendrix go 0-for-4 passing, with only one pass coming anywhere near a receiver. Kelly, who has said Hendrix has looked solid in practice, couldn't explain why the senior looked so inept against the Trojans (4-3). He said it probably was a combination of factors.

"He's got to play better, period," Kelly said.

Rees will need to practice several times this week to be ready to play Saturday at Air Force (1-6), Kelly said.

"We're not at a point where we can afford to just roll out there on Saturday," Kelly said.

The biggest problem for the Irish this season might be they don't have someone to come in and provide the kind of spark Rees repeatedly gave the Irish last season. Kelly had hoped to use Hendrix as a change-of-pace quarterback, but the Irish have repeatedly been called for false starts while he's in. Kelly said the coaches probably need to give Hendrix more time practicing with the starters so they get used to him.

"Clearly when he goes in there with the first group, there is something in his voice inflection that's a little bit different. We're going to have to do a better job coaching that," she said.

The Irish are unranked with a record of at least 5-2 for just the fourth time in school history. Three times the Irish were 5-2 and unranked: in 2008 under Charlie Weis, in 2004 under Tyrone Willingham and in 1951 under Frank Leahy, when the Irish dropped out after a 35-0 loss to Michigan State. The Irish also were unranked at 5-1-1 in 1982 under Gerry Faust.

Asked what he thought about not being ranked, Kelly joked, "Must be a conspiracy."

He said he has the Irish ranked on his ballot in the USA TODAY Sports Coaches' Poll.

West Virginia Mountaineers running back Charles Sims (3) runs the ball for a first down during the first quarter against the Texas Tech Red Raiders at Milan Puskar Stadium. Dan Friend, USA TODAY Sports